Aerostatic bearings with micronozzles distributed across their surface are distinguished by a high bearing or load capacity and stiffness, by a good damping behavior, and thus, with a large stability range as well as a low noise level operation. The static properties can be achieved by the area distribution of the micronozzles adjusted or equalized to a predetermined flow resistance, which results in a uniformly high pressure in the bearing gap. Good dynamic properties result if one succeeds in locating the narrowest throttling point of the micronozzles directly at the outlet point into the bearing gap. The low noise level operation results from the capillary effect of the throttling points.
Hitherto, such bearings were manufactured according to DE-PS 34 39 648 by using sintered material, for instance, sintered bronze, as bearing material for at least one of the two bearing faces. An arrangement of the sintered round pellets, approximately the densest pellet package during spreading or distribution, is used as the bearing face. These surfaces are then compacted by rolling, wherein the rolling geometry is selected, in such a way, that only the uppermost pellets or ball layers are plastically deformed. Narrow residual gaps are formed in between respectively three pellets on the uppermost pellet layer due to the spring back phenomenon. By removal of the top half of the uppermost pellet layer, for instance, by diamond cutters, it is achieved to make these residual gaps effective as throttling points directly at the bearing surface. This process is, however, very difficult to control, especially if one wants to set up specific flow resistances of the throttle layer and attempts to achieve a uniform distribution of the throttling points across the bearing surface.
In U.S. Pat. No. 5,110,520 micronozzles distributed across the surface are produced by sealing the sintered porous bearing surface with plastic spray and subsequently opening same again at individual locations by targeted etching.
In DE-PS 32 30 232, a sintered bearing surface is also compacted and subsequently opened to such an extent by etching, that the desired throttling effect is achieved.